Lightning-arrester



UNITED STATES PATENT OFFICE.

' GEORGE H. DBYDEN, 0F BALTIMORE, MARYLAND.

LIGHTNING-ARRESTER.

Application led September 10, 1914. Serial No. 861,125.

To all whom it may concern:

Be it known that I, GEORGE H. DRYDEN, a citizen of the United States, residing at Baltimore city and State of Maryland, have invented certain new and useful Improvements in Lightning-Arresters; and I do hereby declare the following to be a'full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to improvements in the type of arresters in which the electrodes are maintained in a vacuum, and the object in view is increased efficiency.

In the drawings,-

Figure 1 isa perspective view of an arrester embodying the features of the present invention.

Fig. 2 is a longitudinal, vertical section through the arrester cartridge detached.

Fig. 3 is a transverse, vertical section taken on' the plane indicated by line 3 3 of Fig. 2, and looking in the direction indicated by the arrow.

Fig. 4 is a view similar to Fig. 2 of a modified embodiment.

Fig. 5 is a perspective view of a knife fuse detached adapted to be substituted for the knife switch seen in Fig. 1.

Fig. 6 is a diagrammatic showing of a form of connection for the arrester.

Referring to the drawings by numerals, 1

indicates a base, which, though illustrated in a horizontal position, is adapted to be disposed vertically in use. Fixed to and outstanding from base 1 are the clips 2, 2, of a knife switch 3, the clips being connected respectively to binding posts 4 and 5. If preferred, a knife fuse 6 may be substituted for knife switch 3. Clips 7 and 8 outstand from base 1, the former clip being connected with binding post 5 and one of the clips 2, and cli 8 being connected with a binding post 9. etween the clips 7 and 8 is arranged the arrester cartridge A whose axially projecting terminals are mounted respectively in the clips 7 and 8.

The cartridge A consists of a tubular cylinder 10 of appropriate substance, being of metal in the embodiment seen in Fig. 1. Within the cylinder 10 are arranged terminalstoppers 11, 11, of air tight insulating -material, each backed by and held a ainst axial displacement-by a terminal ins ating disk 12 fitted within the respective end portion of the cylinder 10 and held in place therein by the respective end portions of the cylinder being crimped or spun to form an lnwardly extending ange 10 lapping and surrounding the periphery of the respective disk 12. Terminals 13, 18, preferably of metal, have their inner ends embedded in the insulations 11, and each of said terminals has its inner end fixed to a non-fusing conductor 14 projecting axially inwardly from the respective terminal and connected thereto as by a screw or bolt 15 extending through the respective terminal and its engaged conductor 14. The non-fusing conductors 14 may consist of carbon, graphite or the like, and extend inwardly toward each other with their inner ends spaced apart an appropriate distance for forming such a spark gap as can be readily jumped by a static charge but which will afford efective insulation for currents of ordinary usable potential. Each conductor 14 in extending from its terminal 13 projects through an insulator block 16, of glass, porcelain, or other appropriate in-y sulating material, each of which is cylinl drical in form and provided with an annular recess 16 surrounding the respective con.y ductor 14 for a portion'of its length so as to form a cup or receptacle for disintegrated material which is liable to fall from the conductors due to constant arcing between the electrodes, the said conductors 14 comprising two of the electrodes of the arrester. The insulators 16 are spaced apart axially by an interposed tube 17 snugly fitted within cylinder 10, and surrounding and being spaced from the two electrodes 14 a distance equal to the distance between said electrodes, the tube 17 being a conductor of the same substance as electrodes 14 and comprising the third electrode of the arrester. The distance being the same -between any one of the electrodes and any other one, it is obvious that if a static chargevdischarges from one 100 electrode to another alone the result will be due to conditions beyond the arrester, and that conditions being uniform the discharge will take place between an electrode and the other two electrodes, the discharge being 105 thus divided. A binding post 18 is connected to cylinder 10 for the ground wire of the arrester. As the electrode 17 discharges through binding post 18, said electrode may be considered the ground electrode, while 110 the other two electrodes bein connected to line are the line electrodes an consequently the shunt electrodes.

:is seen in F ig. 6, one application of the arrester consists in connecting binding post 4 to line, while binding post 5 is connected to the receiving instrument 19, and the other side of the instrument is connected to line, the latter line having a branch 20 connected with binding post 9. Thus the normal current is not carried through cartridge A, there being no electrical connection for the working current through the cartridge, but instead current is carried from binding post 5 to instrument 19, to the return line of the instrument. If either line becomes statically charged, such charge will not approach instrument 19, but will enter cartridge A either from binding post 5 or through branch 20 and binding post 9. The charge finding its way along one of the electrodes 14 usually divides and discharges in part to the other electrode 14 and in part to electrode 17, the discharge to electrode 14 being neutralized by an induced charge in the line with which said electrode is connected, and the discharge to electrode 17 being grounded.

In the course of manufacture of the cartridge, vacuum is produced therein in any Well known manner, and the insulators 15 qcoperat with cylinder 10 for maintaining the vacuum, so that electrodes 14 and 17 are exposed in a vacuum, the electrode 17 serving also as a heat insulator for preventing cylinder 10 from becoming heated with resulting liability of expansion and loss of vacuum.

It is apparent that in operation the improved arrester provides for a combination of shunt and ground within a vacuum which will effectively dispose of static charges with the least possible resistance so as to ai'ord maximum eticiency in protecting instruments in line without liability of variation in the action of the working current.

In Fig. 4 is illustrated an embodiment of the invention adapted toenable visual ins ection of the arc resulting from static disc arge. In this structure the parts are identical in form and operation with those of the structure above described with the exception of the slight alterations necessary for rendering the electrodes visible. Specifically, the structure consists of-a transparent, preferably glass cylinder 21, to the ends of which are externally threaded caps 22 of metal and within which are arranged the air tight insulators 23, 23, engaged by the cup insulators 24. Between the insulators 24 is arranged the cylindrical electrode 25 which is connected by conductor 26 with the cap 22 at one end, the said cap being engaged by the ground binding post 27. The axially extending electrodes 28, 28,` are spaced within electrode 25, a vacuum being formed and maintained in such space. Esch electrode 28 connects with its respective axial terminal 29 which projects through the respective end of the cartridge and is ada ted to engage a clip 7 or 8 of the form of ase seen in Fig. 1. Electrode 25 is formed with an aperture 25 extending radially from cylinder 21 to the space between electrode 25 and electrodes 28, the aperture 25 being also in line with the gap between electrodes 28, so that any' arcin' occurin within the cartridge will be visib e througlgi the aperture 25. Otherwise the structure operates exactly the same as cartridge A. Of course, each cap 22 has a central aperture surrounding the respective terminals 29 of suiiicient diameter to insure a greater resistance to the assage of electricity from the terminal to tlie cap than the resistance of the gap between electrodes.

Either the knife 3 or the fuse knife 6, as will be apparent, may be used for testing pur oses.

hat I claim is 1. An electric signaling circuit comprising an instrument to be protected from excess voltage, a vacuum chamber, two spaced shunt electrodes therein, connected to said circuit on either side of said instrument, a ground electrode also located in said vacuum chamber, and spaced from each of said shunt electrodes so that three gaps are provided, said gaps being so proportioned to the impedance in the line circuit and in the line to ground as to secure a division of excess voltage current.

2. An electric signaling system comprising a device to be protected from excess voltage, a vacuum chamber, two spaced shunt electrodes therein, a ground electrode also located in the vacuum chamber, and so placed that the shortest distance between it and each of the shunt electrodes is the same as the shortest distance between the two shunt electrodes, the line beyond the vacuum chamber being without gap or substantial reactance.

3. In an arrester, a plurality of electrodes, a transparent tube surrounding said electrodes and a heat insulator within the tube surrounding said electrodes.

4. In an arrester, a plurality of electrodes, a transparent tube surrounding said electrodes, and a heat insulator encircling one of said electrodes.

5. In an arrester, a plurality of electrodes, a transparent tube surrounding 'said electrodes, and a lheat insulator surrounding said electrodes but permitting observation of same.

6. In an arrester, a plurality of electrodes, a transparent tube surrounding said electrodes and providing a vacuum chamber, anda heat insulator surrounding said electrodes but permitting observation of same.

7 In an arrester, the combination with a tubular cylindrical casing, of an insulator in each end portion of the casing having a hermetical engagement therewith, an insulator cup engaging each of said insulators, the cups being spaced apart axially of the cas, ing, a tubular electrode disposed between and engaging the cups, a terminal disposed externally of the casing and electrically connected with said electrode, axially disposed electrodes extending within the first-mentioned electrode and spaced therefrom and spaced apart a distance substantially equal to the distance between the first-mentioned electrode and the second-mentioned electrodes, such distance being suiliciently short to enabley arcing, and terminals for the second-mentioned electrodes projecting axially from within the tubular casing.

8. An electric signaling system comprisin a device to be protected from excess vo tage, a trans arent tube containing a vacuum, a plurality of electrodes therein arranged substantially parallel tothe axis of the tube, a third electrode within the tube so placed that the shortest distance between the third electrode and each of the other elec trodes is the same as the shortest distance between any two of the first-mentioned electrodes, the line beyond the vacuum tube being without gap or substantial reactance.

9. An electric signaling system comprising a device to be protected from ,excess voltage, a transparent vacuum chamber, three electrodes therein so spaced that the 'shortest distance between any two of said electrodes is uniform, line connections to two of said electrodes and from said electrodes to the coil tolbe protected, and a ground connection to the third electrode, whereby any high frequency discharge capable of passing between any of the electrodes will be subdivided and will partly pass to ground, the line beyond the vacuum chamber being without gap or substantial reactance.

10. Anelectric signaling system comprising a device to be protected from excess voltage, a vacuum chamber, a plurality of axially alined spaced shunt electrodes, therein, a tubular ground electrode surrounding the spaced electrodes and spaced therefrom the same distance as the shunt electrodes are spaced apart, the line beyond the vacuum chamber being without gap or substantial reactance.

11. The device of claim 10 characterized by the provision of means permitting a view of the space between the shunt electrodes.

GEORGE H. DRYDEN.

Witnesses:

JNO. J. BAUMGARTNER, EDGAR W. YOUNG. 

